Sulphoxides as solvating reagents for the separation of metal ions

The solvent extraction properties of the following sulphoxides have been evaluated: di-n-octyl sulphoxide (DOSO), bis(n-octylsulphinyl) methane (BOSM), bis(n-octylsulphinyl)ethane (BOSE) and p-tolyl sulphoxide (PTSO). By use of reversed-phase paper chromatography as a qualitative surveying technique, the interactions of these sulphoxides with some fifty metal ions were investigated in several acid-ligand systems. All sulphoxides were studied in 1-10M hydrochloric and nitric adds; DOSO and BOSM were also studied in perchloric acid and ammonium thiocyanate-perchloric acid mixtures. Observations are made concerning sulphoxide-metal interactions and the existence of several useful analytical separation systems is pointed out. The synthesis and characterization of BOSM and BOSE are described.